Plutonium procedure for 200 liters seawater

Risø-R-1263(EN)

Procedures for Determination of 239,240Pu, 241Am, 237Np, 234,238U, 228,230,232Th, 99Tc and 210Pb-210Po in Environmental Materials Qingjiang Chen, Asker Aarkrog, Sven P. Nielsen, Henning Dahlgaard, Bjørn Lind*, A.K. Kolstad* and Yixuan Yu * Norwegian Radiation Protection Authority, Norway

Risø National Laboratory, Roskilde December 2001

ISBN 87-550-2871-3 ISBN 87-550-2966-3 (Internet) ISSN 0106-2840

Print: Pitney Bowes Management Services Denmark A/S, 2001

Contents

Preface 4

Determination of plutonium in 200 liters sea water 4

Plutonium procedure for 200 liters seawater 5

Plutonium procedure for 10 g sediment or soil 7

Plutonium procedure for fish, mussel and other biological samples 8

Plutonium procedure for seaweed 9

Plutonium procedure for 1-2 g sediment or soil 10

Americium procedure for 10 g sediment, soil and 200 liters seawater 11

Neptunium (237Np) procedure for 10 g sediment, soil and seawater 12

Neptunium procedure for sediment and soil 13

Neptunium (237Np) procedure for 100 liters seawater 15

Procedure for simultaneous determination of 237Np and 239,240Pu in 10 g sediment or soil 15

Procedure for simultaneous determination of 239,240Pu and 237Np in 200 liters seawater 17

Determination of uranium in soil and sediment 18

Determination of uranium in food products 20

Determination of thorium in soil and sediment 21

Determination of thorium in food products 22

Determination of 99Tc in 50 liters seawater 23

Technetium-99 procedure for 200 liters seawater 24

Technetium (99Tc) procedure for seaweed-A new method 25

Determination of 210Po and 210Pb in mussel, fish, sediment and petroleum 27

References 30

Risø-R-1263(EN) 3

Preface Since 1987, the Department of Nuclear Safety Research, Risø National Labora-tory has developed procedures for analysis of low-level amounts of radioactiv-ity in large samples of 200 liters seawater, 10 gram sediment, soil and other environmental materials. These analytical procedures provide high chemical yields, good resolution and excellent decontamination factors for large envi-ronmental samples analysed by alpha spectrometry and mass spectrometry (ICPMS). The procedure have been checked through practical analysis work and are used in Norway, the Netherlands, Germany, Spain, France and Den-mark.

Determination of plutonium in 200 li-ters sea water Abstract A procedure for the determination of plutonium in seawater is described. The plutonium is pre-concentrated by scavenging with Fe(OH)2 and Fe(OH)3 .This purifies for Ca2+, Mg2+ and amphoteric elements. The method is based on a new procedure in which the principle of controlled valence is applied. The redox system SO3

2- / NO2- was used (1) first to reduce to

Pu3+ and afterwards to oxidize to Pu4+. The Pu3+ is separated from U and 210Po by solvent extraction with TIOA – 6-10 M HCl. Followed by anion exchange of Pu4+ in 8 M HNO3. The decontamination factors of the procedure are >1.7 ⋅ 106 for U and >6.3 ⋅ 104 for Th. The chemical yield is 70-85%.

Principle Higher valences of plutonium are rapidly reduced to Pu3+ by K2S2O5 in 200 liter seawater at pH=2. Pu(OH)3 and transuranium elements are precipitated by Fe(OH)2-Fe(OH)3 at pH=10. The hydroxide precipitation is repeated twice, the first time to remove a large amount of Ca2+ and Mg2+ at pH=8-10 in a NH3 sys-tem and the second time to separate the amphoteric elements in a 0.3-0.5 M NaOH solution. In order to get rid of the large of amount of sulfur from sulfite (especial in sediment), the sample solution is boiled with H2O2 in 1 M HCl. The reaction is S + 2 H2O2 = H2SO3 + H2O. The H2SO3 is decomposed to H2O and SO2, which is evaporated, or the H2SO3 is further oxidized to H2SO4. The control of valence of plutonium plays an important role in the procedure. Plutonium is reduced to Pu3+ by K2S2O5 and carried by Fe(OH)2 which is dis-solved in 6 M HCl. The UO2Cl4

2-, NpCl62- and PoCl6

2-are extracted into 10%TIOA/xylene. Pu3+,Am3+,Cm3+ and Th4+ are in the aquatic phase, which is evaporated to about 0.5-1 mL. The sample is diluted to 20 mL 0.5 M HCl. The plutonium is reduced to Pu3+ by adding K2S2O5. Then Pu3+ is rapidly oxidized to

4 Risø-R-1263(EN)

Pu4+ by NaNO2 and kept in this oxidation state. The Pu(NO3)62- and Th(NO3)6

2- are absorbed on an AG1-X4 ion exchange column and the Am3+ and Cm3+ are passed through the column in 8 M HNO3. (This elute is kept for later Am de-termination). The column is finally washed with 8 M HNO3 to get rid of the uranium and with 12 M HCl in order to separate the thorium. To avoid plutonium micro absorption on the column wall and on other surfaces, sodium salts are used in every step of the procedure. As yield tracer 242Pu is used.

Plutonium procedure for 200 liters seawater On board the ship

1) Acidify 200 liters seawater to pH=2 with 200 mL 12 M HCl. Add 2 g

FeCl3⋅6H2O, 242Pu, 243Am and 100 g K2S2O5. Stir by bubbling for 1 h to re-duce all Pu valences to Pu3+

2) Basify the 200 liters seawater to pH about =10 with diluted NaOH (0.5-1

M) to precipitate Fe(OH)2-Pu(OH)3-Am(OH)3. The dilute NaOH is added to reduce the formation of Ca(OH)2 and Mg(OH)2. Let stay for 5 h or over-night. Siphon off the supernatant liquid to get about 5 liters of Fe(OH)2 slurry.

3) Acidify the sample to about 0.1 M HCl with concentrated HCl (about 15

mL/liter) Transfer the sample to laboratory for analysis. In the laboratory

4) Slowly add 6% NH3 to pH=9-10. Let stay for 4 h. Pour out the supernatant

liquid. Filter the precipitate on GF/A filter paper under suction. 5) The precipitate is dissolved in 50 mL 12 M HCl + 50 mL 14.4 M HNO3 in a

400 mL beaker. Cover the beaker with a glass disc and heat for 1-2 h to di-gest the sample.

6) Evaporate to about 30 mL and transfer the solution to 250 mL centrifuge

tube. Add NH4OH to pH about 8-9. Centrifuge, Pour the supernatant to re-move the Ca2+and Mg2+.

7) The precipitate is dissolved in 5-10 mL 12 M HCl. Dilute the solution to160

mL with water. Add 150 mg K2S2O5. Stir and let stay for 20 min. Add NaOH to pH=10, centrifuge, and pour the supernatant.

8) The precipitate is dissolved in 20 mL 12 M HCl and 20 mL 6 M HCl. The

concentration of HCl is about 6 M. Transfer the solution to a 250 mL sepa-rator. Extract with 80 mL 10% TIOA/xylene. Shake 5 min. Discard the or-

Risø-R-1263(EN) 5

ganic phase (containing U, Po and Fe). Filter the aquatic phase to the cen-trifuge tube. Add 10 mg Fe+3 and NH3 to pH=10. Centrifuge and pour the supernatant.

9) The sample is dissolved in 5 ml 12 M HCl and dilute to 170 mL. Add 0.5 g

K2S2O5 to sample and stir for 20 min. Add NaOH to pH=10, centrifuge, pour the supernatant.

10) The Fe(OH)2 is dissolved in 2-3 mL 12 M HCl and measure the volume of

solution. Add 50 mg NaNO2. Acidify the to 8 M HNO3 with 14 M HNO3 ( Vs / VHNO3 = 1 /1.3) .

11) The solution is passed through an anion ion exchange column (13 x 1cm,

100-200 mesh AG1-X4) which is equilibrated with 30 mL 1 M HNO3 and 30mL 8 M HNO3 . The flow rate is about 1-1,5mL/min.

12) Wash the column with 20 mL 8 M HNO3 (Combine the passed solution and

the 20 mL washing solution for americium analysis.). ∗Wash the column with 70 mL 8 M HNO3 and 50 mL 12 M HCl. The flow rate is about 1 mL/min.

13) Strip with 80 mL 2 M HCl + 2 g NH2OH.HCl +0.1 g NaCl. 14) Add 4 mL14 M HNO3 and evaporate to dryness. 15) 15) The sample is dissolved in 6 mL 6 M HCl. Transfer the solution to 250

mL centrifuge tube. Wash the beaker and combine the solution to the tube. Dilute to 170 mL. Add 200 K2S2O5 , 30 mg Fe3+ and stir for 20 min. Add NaOH to pH=10, centrifuge and pour the supernatant.

16) The Fe(OH)2 is dissolved in 2 mL 12 M HCl an d dilute to 10 mL with wa-

ter. Add 13 mL 14.4 M HNO3 to 8 M HNO3. 17) Repeat the steps 11). 18) Wash the column with 80 mL 8 M HNO3 and 50 mL 12 M HCl. 19) ∗∗ Strip with 80 mL 2 M HCl + 2 g NH2OH.HCl +0.6 g NaCl.

Electodeposition

20) Add 4 mL 14 M HNO3 and 0.3 mL 18 M H2SO4. Evaporate to dryness on

150oC overnight. Heat at 400oC for 40 minutes. 21) Dissolve the sample in 7 mL 0.05 M H2SO4. Wash the beaker 3 times, each

time with 3 mL 0.05 M H2SO4. Transfer the solutions to a eletrodeposition cell ∗∗∗. Add 2 drops of methylblue and 25%NH3 to pH=2.5. Electrode-posit for 4-5 hours. The current is 0.7A/cm2. Cool the cell with water. Add 0.5 mL 25% NH3 to the cell and let stay for 30 seconds. Switch off the cur-rent.

22) Dismantle the disc from the cell. Hold the disc with tweezers. Dip the disc

into water pH=9 (NH3) 2 times, each time for 2 seconds. The water on the

6 Risø-R-1263(EN)

disc surface is sucked with soft paper. Put the disc in a 90oC heating cabinet for 15 min and the sample is ready for α-measurement.

________________________________________________________________ ∗ Wash the column with 8 M HNO3 and 12 M HCl: In order to increase the efficiency of cleaning and to avoid surface contamination of the glass wall of the column, the solution is added 10 mL by 10 mL. The surface of the column should dry before the next 10 mL is added. ∗∗Strip with 70 mL 2 M HCl + 2 g NH2OH⋅HCl. Add 4 mL 14 HNO3 to the stripped solution and evaporate to dryness. Add 5 mL 14.4 M HNO3 and evaporate to dryness. The sample is dissolved in 4% HNO3 for ICPMS meas-urement. ∗∗∗Preparation of the hydrophilic surface of a disc: The disc is fixed to an elec-trodeposition cell which is checked for leaks. Clean the cell and disc with wash-ing powder solution and polish the surface of the disc with cotton which is hold by tweezers. Wash the cell with distillated water for 10 times. The surface of the disc becomes hydrophilic which is good for electrodeposition. If the disc is washed with alcohol or acetone, the surface of the disc becomes hydrophobic, which is bad for electrodepositon.

Plutonium procedure for 10 g sedi-ment or soil 1) Transfer 10g homogenizes soil or sediment into a beaker. Burn at 550OC

over night. 2) AddAm-243 and Pu-242 tracer, (0.2 g FeCl3 6 H2O for sand sample) and 40

mL aqua regia. Cover with glass disk. Digest for 30 min on 150 oC and for 1 h on 200oC plate. Dilute to 120 mL with water and stir for 1 min. Filter the leaching liquid through a GF/A (with suction). Wash the residue for 3 times each time with 10 mL 0.5 M HCl.

3) Transfer the solution to 250 mL centrifuge tube. Add 12.5% NH3 to

pH=7.5-8.0. Centrifuge and pour the supernatant to remove the Mg2+ and Ca2+. Add 20 mL 6 M NaOH and stir for 5 min. Dilute to 200 mL, stir, cen-trifuge, and pour the supernatant to remove the amphoteric elements.

4) Add 5 mL 12 M HCl and transfer the solution to 500 mL beaker. Wash the

tube with 1 M HCl. The volume is about 40 mL. Add 30 mL 30%H2O2. Heat the solution to remove the sulfur and reduce the volume to about 10 mL.

5) Transfer the solution back to the centrifuge tube and dilute the solution

to160 mL with water. Add 150 mg K2S2O5 and stir for 20 min. Add 6 M NaOH to pH=10, centrifuge, and pour the supernatant.

Risø-R-1263(EN) 7

6) The precipitate is dissolved in 10 mL 12 M HCl and 20 mL 6M HCl. The acidity is 6-8 M. Transfer the solution to a 250 mL separator. Extract with 50 mL 10% TIOA/xylene. Shake 5 min. Discard the organic phase (contain-ing U, Po and Fe). Filter the aquatic phase to the centrifuge tube and dilute to160 mL. Add 10 mg Fe+3 and NH3 to pH=10. Centrifuge and pour the su-pernatant.

7) The precipitate is dissolved in 3-5 mL 12 M HCl and dilute to 170 mL. Add

0.5 g K2S2O5 to sample and stir for 20 min. Add NaOH to pH=10, centri-fuge, pour the supernatant.

8) The Fe(OH)2 is dissolved in 1-3 mL 12 M HCl and measure the volume of

solution. Acidify the to 8 M HNO3 with 14 M HNO3 (Vs / VHNO3 = 1 /1.3). Add 50 mg NaNO2 and stir.

9) The solution is passed through an anion ion exchange column (13 x 1cm,

100-200 mesh AG1-X4) which is equilibrated with 30 mL 1 M HNO3 and 30mL 8 M HNO3 . The flow rate is about 1-1,5mL/min.

10) Wash the column with 20 mL 8 M HNO3. (Combine the passed solution

and the 20 mL washes solution for americium analysis). ∗Wash the column with 60 mL 8 M HNO3 and 50 mL 12 M HCl. The flow rate is about 1 mL/min.

11) Strip with 80 mL 2 M HCl + 2 g NH2OH.HCl +0.1 g NaCl. 12) Add 4 mL14 M HNO3 and evaporate to dryness. 13) The sample is dissolved in 6 mL 6 M HCl. Transfer the solution to 250 mL

centrifuge tube. Wash the beaker and combine the solution to the tube. Di-lute to 170 mL. Add 30 mg Fe3+, 200 mg K2S2O5 and stir for 20 min. Add NaOH to pH=10, centrifuge and pour the supernatant.


ter. Add 13 mL 14.4 M HNO3 to 8 M HNO3. 15) Repeat the steps 9). 16) Wash the column with 80 mL 8 M HNO3 and 50 mL 12 M HCl. 17) ∗∗ Strip with 80 mL 2 M HCl + 2 g NH2OH.HCl +0.6 g NaCl. 18) Preparation for electrodeposition.

Plutonium procedure for fish, mussel and other biological samples 1) Dry and homogenize the samples.

8 Risø-R-1263(EN)

2) Add 10 g fish powder, 242Pu, 243Am, 40 mL 14 M HNO3 and 30 mg Fe3+.

Cover the beaker with a glass disc and digest on 200oC plate for 3 h. Evapo-rate to dryness on 150 0C plate.

3) Burn at 550 0C in oven overnight. Add 40 mL aqua regia. Cover the beaker

with glass disc and digest for 90 minutes. Dilute the solution to 100 mL with water and stir for 1 minute.

4) Filter the solution with GF/A to 250 mL plastic centrifuge tube. Wash the

beaker and the paper with 30 mL 0.2 M HCl. Add NH3 the solution to pH=10. Centrifuge and pour off the supernatant.

5) The precipitate (Fe(OH)3) is dissolved in 3-5 mL 12 M HCl. Dilute the so-

lution to 170 mL. Add 0.3 g K2S2O5 and stir for 20 minutes. Add NaOH to pH = 10, centrifuge and pour the supernatant.

6) Fe(OH)2 is dissolved in 2-3 mL 12 M HCl and measure the volume of sam-

ple. Acidify the solution to 8 M HNO3 with 14 M HNO3(Vs : V HNO3 = 1 : 1.3 ).

7) The solution is passed through an anion ion exchange column (13 x 1 cm,

100-200 mesh AG1-X4) which is equilibrated with 30 mL 1 M HNO3 and 30 mL 8 M HNO3 . The flow rate is about 1-1,5 mL/min.


and 20 mL washing solution for americium analysis). Wash the column with 70 mL 8 M HNO3 and 50 mL12 M HCl. The flow rate is 2-3 mL/min.

9) Strip with 80 mL 2 M HCl + 2 g NH2OH HCl + 0.6 NaCl (without NaCl for

ICPMS). 10) Prepare for electrodeposition.

Plutonium procedure for seaweed 1) Dry the sample to constant weight by oven drying at 110 oC and homoge-

nize the sample. 2) Add 10 g seaweed and 0.5 g NaCl to porcelain crucible and burn the sample

at 700 oC in oven overnight. 3) Add 242Pu, 243Am, 10 mL 12 M HCl and 4 mL 14 M HNO3. Cover the por-

celain crucible with a glass disc and digest for 30 min at 150oC. Add 30 mL 14 M HNO3 more and digest for 90 minutes at 200oC (or transfer the sample to a beaker for digesting). Add 30 mg Fe3+ and 50 mL H2O. Stir for 30 seconds.

Risø-R-1263(EN) 9

4) Filter the solution through a GF/A filter to centrifuge tube. Wash the beaker and the paper with 30 mL 0.2 M HCl. Add NH3 to the solution to pH =8-9. Centrifuge and pour off the supernatant.

5) The precipitate is dissolved in 5 mL12 M HCl and diluted to a 160 mL with

H2O. Add 150 mg K2S2O5, stir and let stay for 20 min. Add NaOH to the so-lution to pH=10 and centrifuge. Pour off the supernatant.

6) Add 5 mL 12 M HCl to dissolve the sample. Transfer the solution to a

separator funnel, wash the tube with 25 mL 6 M HCl and transfer to the funnel. Extract with 40 mL 10%TIOA/xylene. Shake with hand for 20 sec-onds and shake with machine for 5 min. Discard the organic phase.

7) Add 10 mg Fe3+ to the aquatic phase and dilute 150 mL. Add NH3 to

pH=10, centrifuge, pour the supernatant. 8) The precipitate is dissolved in 5 mL 12 M HCl and dilute to 160 ml . Add

0.3 g K2S2O5 and stir for 20 minutes. Add NaOH to pH = 10, centrifuge and pour the supernatant.

9) Fe(OH)2 is dissolved in 2-3 mL 12 M HCl and measure the volume of sam-

ple. Acidify the solution to 8 M HNO3 with 14 M HNO3(Vs : V HNO3 = 1 : 1.3 ).

10) The solution is passed through an anion ion exchange column (13 x 1 cm,

AG1-X4 100-200 mesh) which is equilibrated with 30 mL 1 M HNO3 and 30 mL 8 M HNO3. The flow rate is about 1-1,5 mL/min.


and 20 mL washing solution for americium analysis). Wash the column with 70 ml 8 M HNO3 and 50 ml 12 M HCl. The flow rate is 2-3 mL/min.

12) Strip with 80 ml 2 M HCl + 2 g NH2OH HCl + 0.6 NaCl (without NaCl for

ICPMS). 13) Prepare for electrodeposition.

Plutonium procedure for 1-2 g sedi-ment or soil 1) Transfer 1-2 g homogenizes soil or sediment into a beaker. Burn at 550OC

over night. 2) AddAm-243 and Pu-242 tracer, (0.2 g FeCl3 6 H2O for sand sample) and 20

mL aqua regia. Cover with glass disk. Digest for 30 min on 150 oC and for 1 h on 200oC plate. Dilute to 120 mL with water and stir for 1 min. Filter the leaching liquid through a GF/A (with suction)filter. Wash the residue for 3 times each time with 10 mL 0.5 M HCl.

10 Risø-R-1263(EN)

3) Transfer the solution to 250 mLcentrifuge tube. Add 12.5% NH3 to pH=7.5-

8.0. Centrifuge and pour the supernatant to remove the Mg2+ and Ca2+. Add 20 mL 6 M NaOH and stir for 5 min. Dilute to 200 mL, centrifuge, pour the supernatant to remove the amphoteric elements.

4) The precipitate is dissolved in 5 mL 12 M HCl and dilutes the solution

to160 mL with water. Add 150 mg K2S2O5. Stir for 20 min. Add NaOH to pH=10, centrifuge, and pour the supernatant.

5) The precipitate is dissolved in 5 mL 12 M HCl and 10 mL 6M HCl. The

acidity is about 6 M. Transfer the solution to a 150 mL separator. Extract with 20 mL 10% TIOA/xylene. Shake 5 min. Discard the organic phase (containing U, Po and Fe).

6) Filter the aquatic phase to the centrifuge tube. Add 10 mg Fe+3 and dilute to

160 mL. Add 0.3 g K2S2O5 to sample and stir for 20 min. Add NaOH to pH=10, centrifuge, pour the supernatant.

7) The Fe(OH)2 is dissolved in 2-3 ml 12 M HCl and measure the volume of

solution. Acidify the to 8 M HNO3 with 14 M HNO3 (Vs / VHNO3 = 1 /1.3). 8) The solution is passed through a anion ion exchange column (13 x 1cm,

AG1-X4, 100-200 mesh) which is equilibrated with 30 mL 1 M HNO3 and 30 mL 8 M HNO3. The flow rate is about 1-1,5mL/min.


and the 20 mL washing solution for americium analysis. ). ∗Wash the col-umn with 50 mL 8 M HNO3 and 50 mL 12 M HCl. The flow rate is about 1 mL/min.

10) Strip with 80 mL 2 M HCl + 2 g NH2OH.HCl +0.6 g NaCl. 11) Preparation for electrodeposition.

Americium procedure for 10 g sedi-ment, soil and 200 liters seawater 1) Add 10 mg Fe3+ to the americium fraction from the plutonium analysis and

dilutes to 130 mL in a 250 mL centrifuge tube. Add NH3 to pH about 8, centrifuge and pour the supernatant.

2) The precipitate is dissolved in 3 mL 12 M HCl. Add 1 mL 30% H2O2, And

0.5 g CaCl22H2O and stir. Dilute to 140 mL with water. Add 30 mL 100 mg/mL H2C2O42H2O under stirring. Add 2.0 mL 25%NH3 to pH =1-1.5 to get white precipitate. Centrifuge for 10 min. at 3000 r.p.m. Pour off the su-pernatant. Wash the precipitate with 150 mL 0.1 M HCl + 3 mL 30% H2O2,

Risø-R-1263(EN) 11

3 mL 100 mg/mL H2C2O42H2O and stir. Centrifuge for 10 minutes. Pour off the supernatant.

3) Add 1 mL 12 M HCl + 0.3 mL 14 M HNO3 + 10 mL 30% H2O2. Cover the

tube with glass filter. Heat in water bath (on a 2200C plate) for 2 h to de-stroy the C2O4

2-. Add 2 mL 14 M HNO3 and heat for 10 min. Add 140 mL H2O, 10 mg Fe+3 and stir. Add 3% NH3 to pH=6.5-7. Centrifuge for 10 minutes. Pour off the supernatant. Wash the precipitate with 160 mL H2O pH=6.7 (NaOH) and stir for 20 minutes. Centrifuge and pour off the super-natant.

4) Add 3 mL 12 M HCl. Transfer the solution to 150 mL separator. Wash the

beaker with 15 mL 6 M HCl and transfer the washing solution to the separa-tor. Extract with 20 mL 10%TIOA/xylene (Po, U, Pu and Fe+3 in organic phase). Shake for 5 min. Discard the organic phase. Evaporate the aquatic phase to dryness. Add 5 ml 14 M HNO3 and evaporate to dryness. Add 3 ml 14 M HNO3 and evaporate to dryness again.

5) Add 10 mL 8 M HNO3 to dissolve the sample. The solution is passed

through the column (12 x 1 cm, 100-200 mesh, AG1-X4) which is equili-brated with 20 mL 1 M HNO3 and 20 mL 8 M HNO3. Wash the column with 15 mL 8 M HNO3. Thorium is absorbed on the column. Collect the passed solution and washing solution. Evaporate the solution to dryness.

6) The sample is dissolved in 1.5 mL 14 M HNO3. Add 0.3 mL30% H2O2, stir

and let stay for 2 min. Add 25 mL CH3OH and stir. The solution is passed through the column (12 x 1 cm, AG1-X4,100-200 mesh)which is equili-brated with 25 mL 1 M HNO3 and 20 mL 1 M HNO3-93% methanol. The flow rate is about 1 mL/min.

7) Wash the column with 20 mL 1 M HNO3-93% methanol, 100 mL 0.1 M

HCl- 0.5 M NH4SCN-80% methanol and 50 mL 1 M HNO3-93% methanol. 8) Strip with 50 mL 1.5 M HCl - 86% methanol + 50 mg NaCl. Evaporate the

stripped solution to dryness. Add 15 mL 14 M HNO3 and 2 ml 3 M NaNO3. Cover the beaker with glass disc. Digest for 30 min. Evaporate to dryness.

9) Preparation for electrodeposition.

Neptunium (237Np) procedure for 10 g sediment, soil and seawater Abstract

Procedures for determination of neptunium in soil, marine sediment and sea-water samples are described. Iron hydroxide Fe(OH)2-Fe(OH)3 is used for pre-liminary preconcentration of neptunium. Secondly, neptunium Np4+ and Pu3+ are separated by tri-isooctylamine (TIOA)/xylene extraction in 8-10 M HCl by redox with SO3

2--Fe3+. Neptunium Np4+ and uranium U6+ are separated by back

12 Risø-R-1263(EN)

extraction of Np4+ with 2 M HCl. Finally, the neptunium is purified from ura-nium and thorium by anion exchange in 8 M HNO3 and 12 M HCl. Neptunium Np3+ and uranium are further separated by stripping with 6 M HCl + NH2OHHCl. Redox with SO3

2- -Fe3+ appeared to be an efficient way to obtain Np4+. The decontamination factors of the procedure are 4.104 for 232Th, 5.6. 104for uranium and 1.6 ⋅104 for plutonium Principle

High valences of neptunium are reduced to Np4+ by K2S2O5 +FeCl3 in 100 liters seawater at PH=2. The Np(OH)4 and transuranium elements are carried by a Fe(OH)2- Fe(OH)3 precipitation at pH=10. The hydroxide precipitation is re-peated twice, the first time to remove a large amount of Ca2+ and Mg2+ at pH=8 in NH3 system and the second time to separate the amphoteric elements in a 0.3-0.5 M NaOH solution. In order to get rid of the large of amount sulfur from sul-fite (especial in sediment), the sample solution is boiled with H2O2 in 1 M HCl. The reaction is S + 2 H2O2 = H2SO3 + H2O. The H2SO3 is decomposed to H2O and SO2, which is evaporated, or the H2SO3 is further oxidized to H2SO4. Control of the valence of the neptunium plays an important role in the proce-dure. Neptunium is reduced to Np4+ by the redox system SO3

2- -Fe3+ and precipitated with Fe(OH)2 which is dissolved in 10 M HCl. NpCl6

2- and UO2Cl4

2- are extracted into10% TIOA/xylene (The aquatic phase contains Pu3+, Am3+ and Cm3+ are collected for Pu and Am analyses). Neptunium is backextraced in 2 M HCl solution and uranium is kept in the organic phase. Np4+ is prepared by adding K2S2O5 + FeCl3 to the back extraction solution which is neutralized to pH=10. After centrifuging, the Fe(OH)2 is dissolved in 1 mL 12 M HCl and acidified to 8 M HNO3. The solution is passed through the anion exchange column. The column is eluted with 8 M HNO3 for separation of uranium and the column is eluted with 12 M HCl for thorium decontamination. Neptunium is stripped with 6 M HCl + NH2OH⋅HCl + NH4Cl. After the stripping, 14.4 M HNO3 is added and the solution evaporated to dryness. (a) The sample is dissolved in 4% HNO3 for ICPMS measurement (b) The source for α-measurement is prepared. The chemical yield of 237Np is determined by internal standard addition, i.e. splitting the sample in two parts, adding known of 237Np to one the aliquots, and then analysing the two parts under identical circumstances.

Neptunium procedure for sediment and soil 1) Dry the sample to constant weight in an oven at 110oC and homogenise the

sample. 2) Add 10 g sample to a 125 mL beaker and burn at 550 oC in an oven over-

night. Add 239Np tracer and 60 mL aqua regia to the sample. Stir for 1 min. Cover the beaker with a glass disc and digest for 30 min at 150oC and for

Risø-R-1263(EN) 13

1 h at 200oC. Add 100 mL H2O, 0.2 g FeCl3 and stir for 1 minute. Filter the sample through a GF/A filter by suction. Discard the residue.

3) Transfer the sample to 250 mL plastic centrifuge tube. Add NH3 to pH=8-9,

centrifuge, pour the supernatant (to remove the Ca2+ and Mg2 ). Add 20 mL 6 M NaOH, stir, dilute 180 mL, stir. Centrifuge and pour the supernatant.

4) The precipitate is dissolved in 5 mL 12 M HCl, dilute to 40 mL and transfer

the solution a 500 mL beaker. Add 30 mL 30% H2O2. Digest for 15 minutes and evaporate to about 10 mL (to remove the sulphur).

5) Transfer the solution back the centrifuge tube and dilute to 170 mL. Add 0.5

g K2S2O5 and stir for 20 minutes. Add NaOH to pH =10, centrifuge and pour the supernatant. The precipitate is dissolved in 12 M HCl (about 40 mL) and the last volume is up to 50 mL. The concentration of HCl should be 8-10 M.

6) Extract with 50 mL 10% TIOA/xylene. Shake for 5 min. Discard the

aquatic phase (Pu3+, Am3+ and Th). Wash the organic phase with 50 mL 10 M HCl. Shake for 5 min. Discard the aquatic phase.

7) Back-extract for 3 times, each time with 20 mL 2 M HCl + 2 drop3 M

NaCl. Shake 5 min Discard the organic phase (UO2Cl42- and PoCl6

2-). Filter the back extraction solution with GF/A into a centrifuge tube, and dilute the solution to 150 mL.

8) Add 30 mg Fe3+ and 200 mg K2S2O5 to the solution. Stir for 20 min. Add

NaOH to pH=10, centrifuge, and discard the supernatant. 9) The Fe(OH)2-Np(OH)4 is dissolved in 2-3 mL 12 M HCl and measure the

volume. Acidify to 8 M HNO3 with 14 HNO3 (Vs : V HNO3 = 1 : 1.3 ). Stir and let stay for 20 min. The solution is passed through the anion exchange column (14 x 1 cm, 100-200 mesh, AG1-x4) which is equilibrated with 25 mL 1 M HNO3 and 30 mL 8 M HNO3. The flow rate is 1 ml/min.

10) Wash the column with 80 mL 8 M HNO3(to remove U, Fe3+) and wash with

50 mL12 M HCl (to remove Th4+) 11) Strip with 80 mL 6 M HCl + 2 g NH2OHHCl. 12) Add 2 mL 14 M HNO3 to the solution. Cover the beaker and digest for 30

min on 200oC plate. Evaporate the solution to dryness on a 150oC plate. Add 2 mL 14 M HNO3 and evaporate to dryness and heat to volatise the NH4NO3.

13) a) The sample is dissolved in 10 mL 4% HNO3 for ICPMS measurement

or b) Add 2mL 3 M NaNO3 and prepare for electrodeposition.

14 Risø-R-1263(EN)

Neptunium (237Np) procedure for 100 liters seawater 1) Add 100 mL 12 M HCl to 100 litres seawater to pH about 2. Add 239Np

tracer, 2 g FeSO4.7H2O and 100 g K2S2O5. Stir with air bubbles for 30 min. Add NaOH to the seawater to pH=10. Let stay overnight.

2) Siphon the supernatant. Transfer the precipitate to a bottle (small tank) and

acidify the sample to pH about 1 with HCl. Stir and let stay for 20 min to dissolve the Ca(OH)2. Add NH3 to pH=10 (to remove Ca2+). Filter the pre-cipitate with GF/A under suction. Wash the precipitate with 100 mL NaOH pH=10.

3) The precipitate is dissolved in 40 mL 12 M HCl and 40 mL 14 M HNO3 in

a 500 mL beaker. Cover the beaker with a glass disc and digest for 90 min-utes on a 200oC plate. Dilute to 100 mL. Filter the solution with a GF/A to 250 ml plastic centrifuge tube. Add 25% NH4OH to pH=10, centrifuge and pour the supernatant. Go to the step 4) of the sediment procedure.

Procedure for simultaneous determi-nation of 237Np and 239,240Pu in 10 g sediment or soil

Application

Plutonium and neptunium are quantitatively scavenged by Fe (OH)2 and Fe(OH)3 in basic solution. In redox SO3

2- - Fe3+ system in weak HCl solution, plutonium and neptunium are kept as Pu3+, Np4+ which are carried by Fe(OH)2 at pH = 10. While the Fe(OH)2 is dissolved in 2-3 mL 12 M HCl and then acidified to 8 M HNO3 with concentrated HNO3 (65%) the Pu3+ is oxidised to Pu4+ by HNO3/ HNO2 (E0=0.94v) and HNO3/N2O4 (Eo=0.79v), and neptunium is still kept as Np4+. Np(NO3)6

2- and Pu(NO3)62- are formed in the 8 M HNO3 solu-

tion. Both complexes are absorbed on the anion exchange column. Uranium is eluted with 8 M HNO3 and thorium with 12 M HCl. The Pu and Np are stripped with 2 M HCl + 2 g NH2OHHCl, which reduces Pu and Np to +3 valence. The sample is evaporated to dryness and dissolved in 4% HNO3 for ICPMS meas-urement. 1) Transfer 10g of homogenized soil or sediment to a beaker. Burn at 550OC

over night. 2) Add 242Pu tracer, 243Am(0.2 g FeCl3 6 H2O for sand sample) and 60 mL

aqua regia. Cover with glass disk. Digest for 30 min at 150 oC and for 1 h on 200oC plate. Dilute to 120 mL with water and stir for 1 min. Filter the

Risø-R-1263(EN) 15

leaching liquid through a GF/A (with suction). Wash the residue 3 times each time with 10 mL0.5 M HCl and combine the washing solutions to fil-trate.

3) Transfer the solution to 250 mL centrifuge tube. Add 12.5% NH3 to pH=10.

Centrifuge and pour the supernatant to remove Ca2+. Add 20 ml 6 M NaOH and stir for 5 min. Dilute to 200 mL, centrifuge, discard the supernatant to remove the amphoteric elements.

4) Add 5 mL 12 M HCl and transfer the solution to a 500 mL beaker. Wash

the tube with 1 M HCl. The volume is about 40 ml. Add 30 mL 30%H2O2 and heat to reduce the volume to about 10 mL(to remove the sulfur).

5) Transfer the solution back to the centrifuge tube and dilute the solution

to160 mL with water. Add 0.5 g K2S2O5. Stir for 20 min. Add NaOH to pH=10, centrifuge. and discard the supernatant.

6) The Fe(OH)2 is dissolved in about 3 mL 12 M HCl. Measure the volume of

the solution. Acidify the solution to 8 M HNO3 with 14.4 M HNO3 (Vs / VHNO3 = 1 /1.3).

7) The solution is passed through a anion ion exchange column (13 x 1cm,

100-200 mesh AG1-X4) which is equilibrated with 30 mL 1 M HNO3 and 30 mL 8 M HNO3 . The flow rate is about 1-1,5 mL/min.


and the 20 mL washing solution for americium analysis. ). ∗Wash the col-umn with 50 mL 8 M HNO3 and 50 mL 12 M HCl. The flow rate is about 1 mL/min.

9) Strip with 80 mlL 2 M HCl + 2 g NH2OH.HCl and 50 mL 0.5 M HNO3. 10) Add 4 mL 65% HNO3 to decompose the NH2OH⋅HCl and evaporate to dry-

ness. 11) The sample is dissolved in 6 mL 6 M HCl. Transfer the solution to a 250

mL centrifuge tube. Wash the beaker and combine the solution to the tube. Dilute to 170 mL. Add 0.3 g K2S2O5 , 30 mg Fe3+ and stir for 20 min. Add NaOH to pH=10, centrifuge and discard the supernatant.


ter. Add 13 mL 14.4 M HNO3 to 8 M HNO3. 13) Repeat step 7). 14) Wash the column with 70 mL 8 M HNO3 and 50mL12 M HCl. 15) Strip with 80 mL2 M HCl + 2 g NH2OH.HCl and 50 mL 0.5 M HNO3. 16) ∗Add 3 mL 2 M NaNO3, 0.3 ml 18 M H2SO4 and 4 mL 14.4 M HNO3 to the

stripping solution. Evaporate to dryness at150oC overnight. Heat at 400oC for 40 min. for electrodeposition.

16 Risø-R-1263(EN)

∗Add 3 mL14.4 M HNO3 to percolate and evaporate to dryness. Add 5 mL14.4 M HNO3 and evaporate to dryness again. The sample is dissolved in 10 mL 4% HNO3 for ICPMS measurement.

Procedure for simultaneous determi-nation of 239,240Pu and 237Np in 200 li-ters seawater On board the ship

1) Acidify 200 liters seawater to pH=2 with 200 mL 12 M HCl. Add 2 g

FeCl3.6H2O, 242Pu, 243Am and 100 g K2S2O5. Stir by bubbling for 1 h to re-duce all plutonium valences to Pu3+ and all neptunium valences to Np4+.

2) Basify the 200 liters seawater to pH about =10 with 800 mL 6 M NaOH(

Dilute to 0.5-1 M) to precipitate Fe(OH)2-Pu(OH)3-Np(OH)4-Am(OH)3. Di-luted NaOH is added to reduce the formation of Ca(OH)2 and Mg(OH)2. Let stay for 5 h or overnight. Siphon off the supernatant liquid to get about 5 li-ters of Fe(OH)2 slurry.

3) Acidify the sample to about 0.1 M HCl with concentrated HCl (about 15

mL/liter) Transfer the sample to laboratory for analysis. In the laboratory

4) Slowly add 6% NH3 to pH=10. Let stay overnight. Discard the supernatant

liquid. Filter the precipitate on GF/A filter paper under suction (or centri-fuge).

5) The precipitate is dissolved in 30 mL 12 M HCl + 30 mL 14.4 M HNO3 in a

200 mL beaker. Cover the beaker with a glass disc and heat for 1-2 h to di-gest the sample.

6) Evaporate to about 30 ml and filter the solution with GF/A to a 250-mL

centrifuge tube. Dilute to 120 mL. Add 25%NH4OH to pH about 10. Centri-fuge, Pour the supernatant to remove the Ca2+and Mg2+.

7) The precipitate is dissolved in 5 mL 12 M HCl. Dilute the solution to160

mL with water. Add 0.5 g K2S2O5. Stir with magnetic stirrer for 20 min. Add NaOH to pH=10, centrifuge, and discharged the supernatant.

8) The Fe (OH)2 is dissolved in 5 mL 12 M HCl. Measure the volume of the

solution. Acidify to 8 M HNO3 with 14 M HNO3 (Vs / VHNO3 = 1 /1.3). 9) The solution is passed through an anion ion exchange column (13 x 1cm,

100-200 mesh AG1-X4) which is equilibrated with 30 mL 1 M HNO3 and 30mL 8 M HNO3. The flow rate is about 1-1,5mL/min.

Risø-R-1263(EN) 17


and the 20 mL washes solution for americium analysis. ). ∗Wash the col-umn with 50 mL 8 M HNO3 and 50 mL 12 M HCl. The flow rate is about 1 mL/min.

11) Strip with 80 mL 2 M HCl + 2 g NH2OH.HCl +50 mL 0.5 M HNO3. 12) Add 4 mL14.4 M HNO3 to decompose and evaporate to dryness. 13) The sample is dissolved in 6 mL 6 M HCl. Transfer the solution to a 250

mL centrifuge tube. Wash the beaker with 30 mL 0.5 M HCl and combine the solution to the tube. Dilute to170 mL. Add 0.3 g K2S2O5, 30 mg Fe3+ and stir for 20 min. Add NaOH to pH=10, centrifuge and discharged the su-pernatant.

14) The Fe(OH)2 is dissolved in 2 mL 12 M HCl an d dilute to 10 ml with wa-

ter. Add 13 ml 14.4 M HNO3 to 8 M HNO3. 15) Repeat step 9). 16) Wash the column with 70 mL 8 M HNO3 and 50 mL 12 M HCl. 17) Strip with 80 mL 2 M HCl + 2 g NH2OH.HCl + 50 ml 0.5 M HNO3. 18) a) Add 4 mL 14.4 M HNO3 and evaporate dryness. Add 5 mL14.4 M HNO3

and evaporate to dryness. The sample is dissolved in 10 mL 4% HNO3 for ICPMS measurement.

19) Add 3 mL 2 M NaNO3, 0.3 mL 18 M H2SO4 and 4 mL 14.4 M HNO3 to the

stripping solution. Evaporate to dryness on a 150oC plate overnight. Heat at 400oC for 40 min for electrodeposition.

Determination of uranium in soil and sediment Application The leaching solution of an environmental sample (or after polonium is re-moved by thermal deposition) is treated with FeCl3 + Na2SO3 and acidified to 6-10 M HCl. The solution is passed through the anion exchange column. UO2Cl4

2-

, FeCl4- and PoCl6

2-are absorbed on the column and Th4+, Pu3+, Am3+, Fe2+ and bulk material are passed through. The column is eluted with 6 M HCl for clean Th4+, Pu3+, Am3+ and Fe2+, and with 5 M HNO3-9% H2O2 to get off the Fe3+. Uranium is stripped with 5 M HNO3 and polonium is removed by thermal depo-sition before prepared for uranium electrodeposition.

18 Risø-R-1263(EN)

1) 0.3-1 g soil or sediment, 232U, 208Po and 12 aqua regia are added to 150 mL beaker. The sample is stirred to homogeneity and the beaker is covered with a glass disc, and heated for 90 minutes on 150-2000C plate. The isotope ex-change should be completed.

2) Dilute the leaching solution to100 ml with water and stir. Filter the solution

through a filter GF/A into centrifuge tube. 3) Add 25%NH3 to pH=10 to form Fe(OH)3 and centrifuge for 10 min. at 300

r.p.m. Discard the supernatant. 4) The Fe(OH)3 is dissolved in 1 mL 12 M HCl and the solution is transferred

to glass tube, and the centrifuge tube is washed with 30 ml 0.1 M HCl and combined to the glass tube for polonium thermal deposition on silver disc ( see polonium analysis) which is ready for polonium α-measurement.

5) The solution is transferred to beaker. Add 3 ml 14 M HNO3 to the sample

and evaporate to dryness. The sample is dissolved in 6 ml 6 M HCl and transferred to the centrifuge tube, and diluted to 150 ml. Add 0.3 g Na2SO3 stir with magnetic stirrer for 10 min and adjusted with NaOH to pH=10 to form Fe(OH)2 and centrifuge for 10 min. Discard the supernatant.

6) The Fe(OH)2 is dissolved in 2 mL HCl. Measure the volume of the solu-

tion. Acidify the solution to 6-8 M HCl. 7) The solution is passed through the column (14 x 1 cm, 100-200 mesh AG1-

X4) which is equilibrated with 20 mL 6 M HCl. (UO2Cl42-, FeCl4

- and PoCl6

2-are absorbed on the column and Th4+,Fe2-, Pu3+, Am3+and bulk mate-rial are passed through)

8) The column is eluted with 50 mL 6 M HCl to clean for Th4+, Fe2- and Pu3+.

and with 25 mL 5 M HNO3-9% H2O2 (3 mL by 3 mL) to clean for Fe3+. Pressurised a air is applied to the liquid surface of the column to get rid off the large amount of bubbles.

9) Strip with 50 mL 5 M HNO3.

a) Evaporate the eluate to dryness. Add 5 mL HNO3 and evaporate to dry-ness again. The sample is dissolved in 10 mL 4% HNO3 for ICPMS measurement.

b) ml 3 M NaNO3 and 0.3 mL 18 M H2SO4 are added to the strip solution and evaporated to dryness on 150 0C. Heat at 400 0C for 40 min. for elec-trodeposition

Risø-R-1263(EN) 19

Determination of uranium in food products

1) Add 10 g ash of potato (or brown bread, cod, beef and 5 g ash of milk) to a

200 mL beaker and cover with a glass disc to protect contamination of U and Th from oven wall. Burn at 600 0C in oven for 3 days.

2) Add tracer 232U, 229Th, 208Po 1g NaNO3, 10 mL 12 M HCl and 10 mL 14 M

HNO3 to the beaker which is covered with a glass disc. Heat at 150 0C for 1 h and evaporate to dryness. Add 10 mL 14 M HNO3 and evaporate dry-ness again. Heat at 200 0C for 10 min and 300 0C for 1 h.

3) Cover the beaker with the glass disc and burn at 550 0C over night. Add 40

mL aqua regia and digest for 30 min on 150 0C and for 1 h on 200 0C. 4) Dilute to 120 mL and add 10 mg Fe3+. Filter the sample through a GF/A

filter to 250 mL plastic centrifuge tube. Add 25% NH3 to pH =10 and cen-trifuge, pour off the supernatant.

5) The precipitate is dissolved in 10 mL HCl and diluted to 150 mL, and 0.3 g

NaSO3 is added during stirring for 10 min. Add NaOH to pH = 10, centri-fuge and discard the supernatant.

6) The precipitate is dissolved in 10 mL 12 HCl and the volume of sample so-

lution is measured. Then acidify to 6 M HCl. 7) The solution is passed through the column (14x1 cm, Ag1-X4, 100-200

mesh) which is equilibrated with 30 mL 6 M HCl and eluted with 60 mL 6 M HCl, and 25 mL 5 M HNO3-9% H2O2 (with pressure air to get rid of the bobbles from the column.)

8) ∗First strip with 50 mL 5 M HNO3 for uranium. 9) Evaporate the uranium fraction to dryness and add 5 mL 12 M HCl. Evapo-

rate to dryness again. The sample is dissolved in 30 mL 0.3 M HCl for po-lonium thermal deposition in order to avoid Po contamination in the U-fraction. Discard the silver disc with the polonium.

10) Transfer the solution to the beaker and add 4 mL 14 M HNO3, and evapo-

rate to dryness. The sample is dissolved in 15 mL 6 M HCl. 11) The solution is passed through the column (14x1 cm, Ag1-X4, 100-200

mesh) 12) which is equilibrated with 30 mL 6 M HCl. The column is eluted with 60

mL M HCl, and 25 mL 5 M HNO3-9% H2O2 (with pressure to get off the bobbles from the column.)

20 Risø-R-1263(EN)

13) Strip with 50 mL 5 M HNO3.

a) The sample is evaporated to dryness and dissolved in 10 mL 4% HNO3 for ICPMS measurement.

b) Add 0.3 mL 18 M H2O4 and 2 mL 3 M NaNO3 and evaporate to dry-ness. Heat at 400 0C for 40 min. for electrodeposition.

* (The second strip with 5 mL H2O, 6 ml 1 M NaOH and 100 mL 0.5 M

HNO3. Evaporate to dryness. Add 5 mL 12 M HCl and evaporate to dryness again. The sample is dissolved in 3 mL 0.3 M HCl with 1 g NH2OHHCl for polonium thermal deposition).

Determination of thorium in soil and sediment Application

The sample solution is free from Cl- by repeat evaporating and boiled in 2 M HNO3 with K2S2O8 to oxidise to PuO2

2+. In 8 M HNO3, Th(NO3)6-2 is absorbed

on an anion exchange column, while PuO2(NO3)42- and UO2(NO3)4

2- is passed through. Thorium is stripped with 8 M HCl.

Procedure

1) 0.3-1 g soil or sediment, 229Th tracer and 12 mL aqua regia are added to 150

mL beaker. The sample is stirred to homogeneity and the beaker is covered with a glass disc, and heated for 90 minutes on a 150-2000C plate. The iso-tope exchange should be completed.

2) Dilute the leaching liquid to100 mL with water and stir. Filter the solution

through a GF/A filter to 250 mL plastic centrifuge tube. 3) Add 25%NH3 to pH=10 to form Fe(OH)3 and centrifuge for 10 min. at 300

r.p.m. Pour off the supernatant. 4) The sample is dissolved in 5 mL 14 M HNO3 and transferred to beaker.

Wash the tube with 5 mL 14 M HNO3 and combine the solution to the beaker. Evaporate the solution to near dryness. Add 5 mL 14 M HNO3 and evaporate to near dryness again.

5) Add 5 mL 2 M HNO3 and 0.3 g Na2S2O8, stir and evaporate to near dryness

to get PuO22+. The sample is dissolved in 15 mL 8 M HNO3.

6) The solution is passed through the anion exchange column (14 x 1 cm,

AG1-X4.100-200 mesh) which is equilibrated with 30 mL 2 M HNO3 and 30 mL 8 M HNO3. Th(NO3)6

-2 is absorbed on the column while

Risø-R-1263(EN) 21

PuO2(NO3)42- and UO2(NO3)4

2- is passed through the column. Elute the col-umn with 70 mL 8 M HNO3.

7) Strip with 60 mL 8 M HCl (PuO2Cl4

2- and UO2Cl42- are absorbed on the

column).

a) Evaporate to dryness. Add 10 mL 65% HNO3 and evaporate to dryness again. The sample is dissolved in 10 mL in 4% HNO3 for ICPMS measure-ment. b) Add 0.3 mL H2SO4 and 2 mL 3 M NaNO3 to the strip solution and evaporate to dryness. Heat at 400 0C for 40 minutes. It goes to electrode-position and α- measurement.

Determination of thorium in food products 1) Add 10 g ash of potato (or brown bread, cod, beef and 5 g ash of milk) to a

200 beaker and cover with a glass disc to protect from U and Th contamina-tion from oven wall. Burn at 600 0C in oven for 3 days.

2) Add 229Th tracer, 1g NaNO3, 10 mL 12 M HCl and 10 mL 14 M HNO3 to

the beaker, which is covered with a glass disc. Heat at 150 0C for 1 h and evaporate to dryness. Add 10 mL 14 M HNO3 and evaporate to dryness again. Heat at 200 0C for 10 min and 300 0C for 1 h.

3) Cover the beaker with a glass disc and burn at 550 0C over night. Add 40

mL aqua regia and digest for 30 min at 150 0C and for 1 h at 200 0C. 4) Dilute to 50 mL. Add 10 mg Fe3+ and filter the sample through a GF/A filter

to a 250 mL plastic centrifuge tube. Add 25% NH3 to pH =10 and centri-fuge. Discard the supernatant.

5) The precipitate is dissolved in 10 mL 14 HNO3. 0.3 g Na2S2O8 is added and

evaporated to near dryness. Add 10 mL 65% HNO3 and evaporate to near dryness. Repeat by adding 10 mL 65% HNO3 two times to get a Cl- free from sample.

6) The sample is dissolved in 30-40 mL 8 M HNO3 and passed through the

column (14 x 1 cm, AG1-X4, 100-200 mesh) which is equilibrated with 30 mL 2 M HNO3 and 30 mL 8 M HNO3. Elute the column with 70 mL 8 M HNO3.

7) Strip with 60 mL 8 M HCl.

a) Evaporate the stripped solution to dryness. Add 10 mL 65% HNO3 and evaporate to dryness again. The sample is dissolved in 10 mL 4% HNO3 for ICPMS measurement.

22 Risø-R-1263(EN)

b) Add 0.3 mL H2SO4 and 2 mL 3 M NaNO3 to the percolate and evapo-rate to dryness. Heat at 400 0C for 40 minutes. It goes to electrodeposition step and α-measurement.

Determination of 99Tc in 50 liters seawater

Abstract A procedure for the determination of 99Tc in seawater is described. Technetium is extracted by anion exchange directly from the seawater. Purification for ru-thenium is accomplished by elution with 1 M NaOH-0.1 M EDTA-NaClO. Fi-nally, technetium is further purified by Fe(OH)3 and TIOA/xylene extraction. The chemical yield is 70-80%. Principle After filtering the seawater is passed through a AG1-X4 anion exchange col-umn. The TcO4

- is very strongly absorbed on an anion exchange Ag1-X4 and RuCl4

- is also absorbed on the anion exchange column. Ruthenium is eluted by 1 M NaOH-0.1 M EDTA-NaClO from the anion column. During the elution, Ru3+ is oxidized to Ru4+ by NaClO and the RuCl4

- is destroyed. The Ru4+ forms a chelate complex Ru-EDTA, which as a neutral compound is eluted from the column. The TcO4

- is still strongly absorbed on the anion column. The TcO4- is

stripped by (65%) HNO3 from the column. U, Th, Pu, Am and Po are very effi-ciently scavenged by Fe(OH)3 from the TcO4

- solution . The technetium is fur-ther purified by TIOA/xylene extraction in 1 M H2SO4. The sample is finally electro-deposited on stainless steel disc and β-counted. The yield is determined by a 99mTc tracer. The chemical yield of procedure is 70-80%. A decontamination factor for ru-thenium of > 2⋅ 105 was obtained by repeating the anion exchange twice. Technetium-99 procedure for 50 liters seawater

1) Filter 50 liters seawater through filters and add 99mTc. Stir to allow the iso-

tope exchange to be completed. Let stay for 30 min. 2) The 50 liters seawater is passed through a column (16 ⋅ 2.5 cm AG1-X4,

100-200 mesh ). The flow rate is 40-42 mL/min. It takes 22-23 hours. 3) Wash the column with 100 mL H2O, 50 mL 1 M NaOH –0.1 M EDTA- 10

mL 15% NaClO, 150 mL 1 M NaOH-0.1 M EDTA-15 mL 15%NaClO(for Ru decontamination), 100 mL 1 M NaOH, 100 mL H2O and 500 mL 1 M HNO3.

Risø-R-1263(EN) 23

4) Strip with 200 mL 14.4 M (65%) HNO3 + 0.1 g NaNO3. The flow rate is about 4 mL/min (the total stripping time is about 50 min).

5) Reduce the 200 mL stripping solution to 1 mL by heating. Add 0.5 mL 5 M

H2SO4 and dilute to 20 mL with H2O. Add 2 mL 15% NaClO. Heat for 10 min.

6) Dilute to 30 mL. Add 0.2 mL (10 mg/mL) AgNO3 and 0.5 mL (10 mg/mL)

FeCl3. Add NaOH to pH=9. Heat for 5 minutes and add 0.5 mL NaClO (if the sample solution becomes black, add more NaClO).

7) Filter the solution. Wash the precipitate 3 times, each time with 3 mL water

pH=9(NaOH). Discard the precipitate (U, Th, Pu, Am, Po and Np). 8) Add 5 mL 10 M H2SO4 and 1 g K2S2O8. Dilute the solution to 50 mL with

water. Transfer the solution to a 250 mL separator. 9) Extract with 40 mL 10% TIOA (tri-isooctylamine)/xylene. Shake for 5 min.

Wash the organic phase 2 times, each time with 40 mL H2O. Shake for 5 min (for U, Th decontamination).

10) Back extract with 20 mL 2 M NaOH. Shake for 2 min. Second back extract

with 5 mL 0.5 M NaOH and shake for 2 min. 11) Evaporate the solution to 20 mL for electrodepostion. The current is 150

mA/cm2. It takes at least 5 h or overnight. 12) Clean the disc for NaOH by dipping it into the H2O for times (hold it with

tweezers), each time for 2 seconds. Heavy flushing will cause loss activity. The chemical yield is 70-80%. β-Counting is carried out after 7 days.

Technetium-99 procedure for 200 li-ters seawater 1) Filter 200 liters seawater through filters and add 99mTc. Stir to allow the iso-

tope exchange to be completed. Let stay for 30 min. 2) The 200 liters seawater is passed through a column (16 X 4 cm AG1-X4,

100-200 mesh). The flow rate is 145-150 mL/min. It takes 22-23 hours. 1) Wash the column with 400 mL H2O, 200 mL 1 M NaOH –0.1 M EDTA+

40 mL 15% NaClO, 600 mL 1 M NaOH-0.1 M EDTA-60 mL 15%NaClO (for Ru decontamination), 400 mL 1 M NaOH, 400 mL H2O and 1000 mL 1 M HNO3.

2) Strip with 600 mL 14.4 M (65%) HNO3 + 0.1 g NaNO3. The flow rate is

about 12 mL/min (the total stripping time is about 50 min). (On boat: meas-

24 Risø-R-1263(EN)

ure the chemical yield of 99mTc. Transfer the sample to laboratory and add 99mTc again for analysis).

3) Reduce the 600 mL stripping solution to 1 mL by heating. Add 0.5 mL 5 M

H2SO4 and dilute to 20 mL with H2O. Add 2 mL 15% NaClO. Heat for 10 min.

4) Dilute to 30 mL. Add 0.2 mL (10 mg/mL) AgNO3 and 0.5 mL (10 mg/mL)

FeCl3. Add NaOH to pH=9. Heat for 5 minutes and add 0.5 mL NaClO. If the sample solution becomes black (TcO4

- →Tc4+), add more NaClO (Tc4+→TcO4

-). 5) Filter the solution. Wash the precipitate 3 times, each time with 3 mL water

pH=9(NaOH). Discard the precipitate (U, Th, Pu, Am, Po and Np). 6) Add 5 mL 10 M H2SO4 and 1 g K2S2O8. Dilute the solution to 50 mL with

water. Transfer the solution to a 250 mL separator. 7) Extract with 40 mL 10% TIOA (tri-isooctylamine)/xylene. Shake for 5 min.

Wash the organic phase 2 times, each time with 40 mL H2O. Shake for 5 min (for U, Th decontamination).

8) Back extract with 20 mL 2 M NaOH. Shake for 2 min. Second back extract

with 5 mL 0.5 M NaOH and shake for 2 min. 9) Evaporate the solution to 20 mL for electrodeposition. The current is 150

mA/cm2. It takes at least 5 h or overnight. 10) Clean the disc for NaOH by dipping it into the H2O for times (hold it with

tweezers), each time for 2 seconds. Heavy flushing will cause loss activity. The chemical yield is 70-80%. β-Counting is carried out after 7 days.

Technetium (99Tc) procedure for seaweed-A new method Principle

In order to avoid the volatilization of technetium at high temperatures, a wet ash method was developed for seaweed analysis. Seaweed is carbonized by concentrated H2SO4. Afterwards the sample is di-gested by concentrated HNO3. After that the normal procedure is followed. Procedure for 10 g seaweed

1) Add 10 g fine dry seaweed power (ground with blender for 1 min) and 20

mL 18 M H2SO4 in a flask. Stir until completely mixed. Let stay at least for 1 h or several days.

Risø-R-1263(EN) 25

2) The seaweed is carbonised by concentrated H2SO4. Add 99mTc, 0.5 mL 10

mg/mL FeCl3 0.3 mL 10 mg/mL AgNO3 and 1 g Na2SO4⋅ H2O. Stir to ho-mogeneity.

3) Add conc. HNO3 (65%) drop by drop to the flask. Be careful, the reaction is

very strong. Continuously add conc. HNO3 (65%) (per g /6-8 mL HNO3) until the reaction is calm.

4) Heat the solution for 2 h (if the solution becomes black colour, add more

HNO3). The solution becomes greenish. Transfer the solution to a 500 mL beaker and dilute to 200 mL. Add 10 g K2S2O8 and heat to boiling for 15 minutes, then dilute to 300 mL.

5) Add 6 M NaOH to the solution until pH=12. Filter the solution with GF/F

15 cm with suction and dilute to about 1000 mL. The solution is passed through the column (12 x 1.5 cm AG 1-X4 100-200 mesh) The flow rate is 1-2 mL/min.

6) Wash the column with 20 mL H2O, 40 mL 1 M NaOH – 0.1 M EDTA + 8

mL 15% NaClO, 30 mL 1 M NaOH, 20 mL H2O and 100 mL 1 M HNO3. 7) Strip the 99Tc with 60 mL 65% HNO3 + 0.1 g NaNO3. The flow rate is

about 1 mL/min 8) Evaporate the solution to 1 mL. Add 4 mL 10 M H2SO4 and dilute to 30

mL, and add 1 g K2S2O8. Transfer the solution to a 150 mL separator. Wash the beaker with 10 mL H2O and transfer to the separator.

9) Add 40 mL 10% TIOA/xylene and shake 3 min. Wash the organic phase 2

times each time with 40 mL H2O and shake for 5 min.(for U, Th decon-tamination)

10) Back extract with 20 mL 2 M NaOH and shake for 2 min. Second time back

extract with 5 mL 0.5 M NaOH and shake for 2 min. 11) Evaporate the solution to 20 mL for electrodeposition. The current is 300

mA/2cm2 the time is at least 5 h or overnight. 12) Clean the disc for NaOH by dipping it (hold with tweezers) careful for

2seconds in 100 mL H2O. Heavy flushing will cause loss of activity. The chemical yield is 80-95.

26 Risø-R-1263(EN)

Determination of 210Po and 210Pb in mussel, fish, sediment and petroleum Abstract

A procedure for the determination of 210Po and 210Pb in mussel, fish, sediment and petroleum has been developed. The sample is digested with HNO3 and HCl, and further digested with H2O2 in 1 M HCl. After wetashing the 210Po is depos-ited on a silver disc by thermal decomposition. Lead-210 is determined by ingrowth of 210Po from 210Pb. A rapid method for separation of 210Po and 210Pb has been developed utilising extraction with Tri-isooctylamine (TIOA)/xylene in HCl + H2O2. PoCl6

2-, UO2Cl42- and FeCl4- are

extracted into TIOA and 210Pb remains in aquatic solution for 210Po ingrowth.

Principle The sample is digested with HNO3 + HCl and evaporated to dryness. The or-ganic matter is further digested with H2O2 in 1 M HCl. Polonium is deposited on a silver disc in a H2OH⋅HCl - 0.3-0.5 M HCl solution and analysed by α-spectrometry. Lead-210 is determined by ingrowth of 210Po from 210Pb. After the deposition, the sample is treated with H2O2 and evaporated to about 5 mL, and acidified to10 M HCl. PoCl6

2-, UO2Cl42- and FeCl4

- are extracted into 5%TIOA/xylene and 210Pb remains in the aquatic solution, which is kept for half a year for the ingrowth of 210Po from 210Pb. Finally the 210Po from ingrowth is deposited on a silver disc and α-counted. Lead-210 is btained from a calculation of the 210Po ingrowth.(see Appendix -2) Procedure for polonium-210 1. To 10 g flesh of mussel (fish) in a 500 mL flask, 208Po, 25 mL 14 M HNO3,

5 mL 12 M HCl and 0.3 g NaCl are added. Condense for 5 h on 250oC plate to digest the flesh. Evaporate to dryness at 120-150 oC plate. Add 10 mL 30% H2O2 1 mL 12 M HCl and evaporate to dryness on a 130oC plate. Add 10 mL 12 M HCl and evaporate to dryness on 120-150oC plate. Go to step 2. (Sediment: Use 0.2- 0.5 g sediment, 208Po, 0.3 g NaCl and 20 mL aqua regia to 150 mL beaker. Digest for 90 min on a 250oC plate. Add 10 mL 14 M HNO3. Digest for 1 h on a 250oC plate. Cool the sample for 15 min with water and dilute to 120 mL with water. Filter the sample through a glass fi-bre paper GF/F to a 250 mL plastic centrifuge tube. Wash the beaker and residue with 10 mL 1 M HCl. Discard the residue. Add NH3 to pH = 9, cen-trifuge and discard the supernatant. The precipitate is dissolved in 1 mL 12 M HCl. Transfer the sample to a glass tube. Wash the centrifuge tube with 30 mL 0.1 M HCl and combine to the glass tube. Goes to step 3).

Risø-R-1263(EN) 27

(Petroleum Sample: Add 0.100-0.500 g petroleum (Stir to uniformity) 208Po, 30 mL 14 M HNO3, 10 mL 12 M HCl and 0.3 g NaCl to 500 mL flask. Di-gest for 5 h on 250oC plate. Evaporate to dryness on 120-130oC plate. Add 20 mL aqua regia and condense for 1 h. on 250oC plate. Evaporate to dry-ness on a 120-150oC plate. Add 10 mL 30% H2O2 (be careful the reaction is very strong) and evaporate to dryness on 120oC plate. Add 10 mL 12 M HCl and evaporate to dryness on 120-150oC plate. Go to step 2).

(Second polonium analysis for calculation of 210Pb: Transfer the storage so-lution to a 500 mL flask. Add 8 mL aqua regia to the container and cover the container with disc condensing for 30 min on 150oC plat. Transfer the aqua regia to the flask. Wash the container 2 times, each time with 2 mL 14 HNO3 and transfer the solutions to the flask. Add 208Po to the flask. Evapo-rate the solution to dryness on a 120oC plate. Add 20 mL aqua regia to the flask and condense for 1 h on 250oC plate. Evaporate to dryness on a 120oC plate. Go to step 2).

2. Add 5 mL 30% H2O2. Digest for 10 min on a 200oC plate.

Add 0.8 mL 12 M HCl. Digest for 10 min on a 200oC plate. Add 15 mL wa-ter. Digest for 15 min on a 200oC plate. Add 1 g NH2OH.HCl. Digest for 10 min. on a 200oC plate. Cool the sample for 15 min with water. Filter the sample through a Munktell Analytical filter paper. Wash the residue and flask 3 times each time with 3 mL 0.3 M HCl containing 1 mg/mL NaCl. The acidity of the 30 mL of filtrate is 0.3-0.5 M HCl.

3. The clean silver disc is fixed in a special Teflon holder (figure-2, see Ap-

pendix -2.) which is suspended by a polyethylene thread in a vertical posi-tion in the solution exposing one side of the silver disc. Pure polonium metal is deposited on the silver disc surface by thermal decomposition at 90oC under magnetic stirring for 3 h.

4. Dip the holder with the silver disc in distilled water twice, each time for 2

seconds. Dismantle the silver disc from the holder and dip the disc into dis-tilled water 2 times, each time for 2 seconds. The water on the disc surface is sucked in with soft paper. Put the disc in 90oC heating cabinet for 15 min and the sample is ready for α - measurement.

Procedure for 210Pb 5. After thermal decomposition of polonium, add 2 mL 30%H2O2 and evapo-

rate the solution to 5 mL on a 150oC plate. Transfer the sample to a 150 mL separator. Wash he beaker with 25 mL 12 M HCl and transfer to the separator to obtain a concentration of 10 M HCl. Extract with 30 mL 5%TIOA/xylene. Shake 3 min. Wash the organic phase with 5 mL 10 M HCl. Shake 3 min. Combine the 2 aquatic phases to stand for 210Po in-growth from 210Pb. Discard the organic phase, which contains Po, Fe, U and Pu.

6. After a suitable ingrowth period (about 6 months), add 208Po and stir to

uniformity. Transfer the solution to a 500 mL flask. Add 8 mL aqua regia to the container cover the container with a disc. Condense for 30 min on a 150oC plate. Wash the container 2 times, each time with 3 mL 14 HNO3. Combine the solutions to the flask. Evaporate to dryness on a 120oC plate.

28 Risø-R-1263(EN)

7. Add 20 mL aqua regia and condense for 1 h on a 250 oC plate. Evaporate to

dryness on a 120oC plate. 8. Repeat the steps 2, 3, 4. 9. According to the ingrown time and second polonium activity to calculate

the 210Pb activity. (See appendix –1)

Risø-R-1263(EN) 29

References 1. Qingjiang Chen et al, Determination of plutonium in environmental samples

by controlled valence in anion exchange, Journal of Radioanalytical and Nuclear Chemistry, Vol. 1723 No. 2(1993) 281-288.

2. R.J.H. Clark, Vanadium, Comprehensive Inorganic Chemistry, Vol. 3, p-

519.

3. Chen Qingjiang et al. A rapid separation of 210Po from 210Pb by TIOA ex-traction, NUK, Risø National Laboratory, Denmark(unpublished)

30 Risø-R-1263(EN)

Appendix-1 Table 1. Ingrowth of Po-210 from 100 Bq Pb-210. Day Po-210

(Bq) Day Po-210

(Bq) Day Po-210

(Bq) Day Po-210

(Bq) Day Po-210

(Bq) Day Po-210

(Bq) Day Po-210

(Bq) Day Po-210

(Bq) 1 0.03 51 19.59 101 37.27 151 50.94 201 61.49 251 69.61 301 75.85 351 80.61 2 0.12 52 19.99 102 37.58 152 51.18 202 61.67 252 69.75 302 75.95 352 80.69 3 0.27 53 20.39 103 37.89 153 51.41 203 61.86 253 69.90 303 76.06 353 80.77 4 0.46 54 20.78 104 38.19 154 51.65 204 62.04 254 70.04 304 76.17 354 80.86 5 0.69 55 21.18 105 38.50 155 51.89 205 62.22 255 70.17 305 76.28 355 80.94 6 0.95 56 21.57 106 38.80 156 52.12 206 62.40 256 70.31 306 76.38 356 81.02 7 1.24 57 21.96 107 39.10 157 52.35 207 62.58 257 70.45 307 76.49 357 81.10 8 1.56 58 22.35 108 39.40 158 52.59 208 62.76 258 70.59 308 76.59 358 81.18 9 1.89 59 22.73 109 39.70 159 52.82 209 62.94 259 70.72 309 76.70 359 81.26

10 2.25 60 23.12 110 40.00 160 53.05 210 63.11 260 70.86 310 76.80 360 81.34 11 2.62 61 23.50 111 40.29 161 53.27 211 63.29 261 71.00 311 76.90 361 81.42 12 3.00 62 23.88 112 40.59 162 53.50 212 63.46 262 71.13 312 77.01 362 81.49 13 3.40 63 24.26 113 40.88 163 53.73 213 63.64 263 71.26 313 77.11 363 81.57 14 3.81 64 24.63 114 41.17 164 53.95 214 63.81 264 71.40 314 77.21 364 81.65 15 4.22 65 25.01 115 41.46 165 54.17 215 63.98 265 71.53 315 77.31 365 81.73 16 4.64 66 25.38 116 41.75 166 54.40 216 64.15 266 71.66 316 77.41 366 81.80 17 5.06 67 25.75 117 42.03 167 54.62 217 64.32 267 71.79 317 77.51 367 81.88 18 5.49 68 26.12 118 42.32 168 54.84 218 64.49 268 71.92 318 77.61 368 81.95 19 5.92 69 26.48 119 42.60 169 55.06 219 64.66 269 72.05 319 77.71 369 82.03 20 6.36 70 26.85 120 42.88 170 55.27 220 64.83 270 72.18 320 77.81 370 82.10 21 6.80 71 27.21 121 43.16 171 55.49 221 65.00 271 72.31 321 77.91 371 82.18 22 7.24 72 27.57 122 43.44 172 55.71 222 65.16 272 72.43 322 78.01 372 82.25 23 7.68 73 27.93 123 43.72 173 55.92 223 65.33 273 72.56 323 78.10 373 82.33 24 8.12 74 28.29 124 44.00 174 56.13 224 65.49 274 72.69 324 78.20 374 82.40 25 8.56 75 28.64 125 44.27 175 56.35 225 65.66 275 72.81 325 78.29 375 82.47 26 9.00 76 29.00 126 44.54 176 56.56 226 65.82 276 72.94 326 78.39 376 82.54 27 9.44 77 29.35 127 44.82 177 56.77 227 65.98 277 73.06 327 78.48 377 82.62 28 9.88 78 29.70 128 45.09 178 56.98 228 66.14 278 73.18 328 78.58 378 82.69 29 10.32 79 30.05 129 45.36 179 57.18 229 66.30 279 73.31 329 78.67 379 82.76 30 10.76 80 30.39 130 45.62 180 57.39 230 66.46 280 73.43 330 78.77 380 82.83 31 11.20 81 30.74 131 45.89 181 57.59 231 66.62 281 73.55 331 78.86 381 82.90 32 11.64 82 31.08 132 46.15 182 57.80 232 66.77 282 73.67 332 78.95 382 82.97 33 12.07 83 31.42 133 46.42 183 58.00 233 66.93 283 73.79 333 79.04 383 83.04 34 12.50 84 31.76 134 46.68 184 58.21 234 67.09 284 73.91 334 79.13 384 83.11 35 12.94 85 32.10 135 46.94 185 58.41 235 67.24 285 74.03 335 79.22 385 83.18 36 13.37 86 32.43 136 47.20 186 58.61 236 67.40 286 74.15 336 79.31 386 83.25 37 13.79 87 32.77 137 47.46 187 58.81 237 67.55 287 74.27 337 79.40 387 83.31 38 14.22 88 33.10 138 47.72 188 59.00 238 67.70 288 74.38 338 79.49 388 83.38 39 14.65 89 33.43 139 47.97 189 59.20 239 67.85 289 74.50 339 79.58 389 83.45 40 15.07 90 33.76 140 48.23 190 59.40 240 68.00 290 74.61 340 79.67 390 83.51 41 15.49 91 34.09 141 48.48 191 59.59 241 68.15 291 74.73 341 79.76 391 83.58 42 15.91 92 34.41 142 48.73 192 59.79 242 68.30 292 74.84 342 79.84 392 83.65 43 16.33 93 34.74 143 48.98 193 59.98 243 68.45 293 74.96 343 79.93 393 83.71 44 16.74 94 35.06 144 49.23 194 60.17 244 68.60 294 75.07 344 80.02 394 83.78 45 17.15 95 35.38 145 49.48 195 60.36 245 68.75 295 75.18 345 80.10 395 83.84 46 17.57 96 35.70 146 49.72 196 60.55 246 68.89 296 75.30 346 80.19 396 83.91 47 17.97 97 36.02 147 49.97 197 60.74 247 69.04 297 75.41 347 80.27 397 83.97 48 18.38 98 36.33 148 50.21 198 60.93 248 69.18 298 75.52 348 80.36 398 84.04 49 99 36.65 149 50.46 199 61.12 249 69.33 299 75.63 349 80.44 399 84.10 50 19.19 100 36.96 150 50.70 200 61.30 250 69.47 300 75.74 350 80.53 400 84.16

18.79

Risø-R-1263(EN) 31

INGROWTH OF PO-210 FROM PB-210

0

20

40

60

80

100

120

0 100 200 300 400 500

TIME (DAYS)

AC

TIVI

TY (B

Q)

Pb-210Po-210

Fig. 1. Ingrowth of Po-210 from 100 Bq Pb-210. The ingrowth of Po-210 shown in Table 1 and in Fig. 1 is calculated from an initial pure Pb-210 activity of 100 Bq. The following half-lives were used: 22.3 y for Pb-210, 5.012 d for Bi-210 and 138.38 d for Po-210.

32 Risø-R-1263(EN)

Risø-R-1263(EN) 33

Bibliographic Data Sheet Risø-R-1263(EN) Title and authors Procedures for Determination of 239,240Pu, 241Am, 237Np, 234,238U, 228,230,232Th, 99Tc and 210Pb –210Po in Environmental Materials Qingjiang Chen, Asker Aarkrog, Sven P. Nielsen, Henning Dahlgaard, Bjørn Lind, A.K. Kolstad and Yixuan Yu ISBN ISSN 87-550-2871-3; 87-550-2966-3(Internet) 0106-2840 Department or group Date Nuclear Safety Research 2001-12-07 Groups own reg. number(s) Project/contract No(s) Sponsorship Pages Tables Illustrations References 33 1 2 3 Abstract (max. 2000 characters) Since 1987, the Department of Nuclear Safety Research, Risø National Labora-tory has developed procedures for analysis of low-level amounts of radioactivity in large samples of 200 liters seawater, 10 gram sediment, soil and other envi-ronmental materials. These analytical procedures provide high chemical yields, good resolution and excellent decontamination factors for large environmental samples analysed by alpha spectrometry and mass spectrometry (ICPMS). The procedures have been checked through practical analysis work and are used in Norway, the Netherlands, Germany, Spain, France and Denmark.

Descriptors

Determination, Procedures, Pu, Am, Np, U, Th, Tc, Pb, Po, large environmental sample, alpha-spectrometry, ICPMS Available on request from Information Service Department, Risø National Laboratory, (Afdelingen for Informationsservice, Forskningscenter Risø), P.O.Box 49, DK-4000 Roskilde, Denmark. Telephone +45 4677 4004, Telefax +45 4677 4013

34 Risø-R-1263(EN)

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Plutonium procedure for 200 liters seawater